Description
filelock is a platform-independent file lock for Python. From 3.22.0 until 4.2.1, SoftFileLock can trust a forged process identifier in a marker that an attacker can modify but cannot remove, allowing an authorized contender such as another process of the holder's account or root to act as a confused deputy, remove the live marker, and admit another holder. This issue is fixed in version 4.2.1.
Published: 2026-10-20
Score: 4.7 Medium
EPSS: n/a
KEV: No
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Remediation

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History

Tue, 20 Oct 2026 17:15:00 +0000

Type Values Removed Values Added
First Time appeared Tox-dev
Tox-dev filelock
Vendors & Products Tox-dev
Tox-dev filelock

Tue, 20 Oct 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 20 Oct 2026 15:00:00 +0000

Type Values Removed Values Added
Description filelock is a platform-independent file lock for Python. From 3.22.0 until 4.2.1, SoftFileLock can trust a forged process identifier in a marker that an attacker can modify but cannot remove, allowing an authorized contender such as another process of the holder's account or root to act as a confused deputy, remove the live marker, and admit another holder. This issue is fixed in version 4.2.1.
Title filelock: SoftFileLock removes a live holder's marker when another user forges the PID in a writable marker
Weaknesses CWE-345
References
Metrics cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N'}


Subscriptions

Tox-dev Filelock
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-20T15:14:56.836Z

Reserved: 2026-10-19T21:30:47.245Z

Link: CVE-2026-112939

cve-icon Vulnrichment

Updated: 2026-10-20T15:14:48.883Z

cve-icon NVD

Status : Received

Published: 2026-10-20T15:17:16.663

Modified: 2026-10-20T16:17:04.630

Link: CVE-2026-112939

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-20T17:30:13Z

Weaknesses